In fact here's a 10-minute hack to add a make test target. With that all you have to do is create a test script in dlls/xxx/tests/foo.test, put the expected output in tests/foo.test.ref (presumably generated by running the test under Windows), add your script to the makefile and run make test.
I've started playing with this, Alexandre, and I had a thought/question: why not put the tests under 'wine/tests'? I recognize the benefit of having a test immediately associated with the implementation. But, I would argue a) that not all tests are going to be specific to one dll b) by placing all the tests together, you make exporting a 'test' package to Windows simpler. c) You centralize the info and allow for good doco d) We can create and sustain a whole Windows make file hierarchy, which would be useful to a test writer in Windows.
(And yes, I ask because I am threatening to actually do some of the work; of course, I'll run out of time shortly, and it will be an empty threat...<g>).
Thoughts?
Jer